OF ANTS AND WAR In the American desert, where resources are scarce, honeypot ants wage war without end. ROB DUNN asks if we can draw parallels between ant and human conflict. HE WAS SEVEN. His dad had just come back from the frontline in World War II, where he worked as a medic. The bombs had not yet fallen on Germany. But father and son did not discuss the war; instead, they talked about insects. The pair went on long country walks to look for beetles, butterflies and, more than anything, ants. The father, Karl Hölldobler, loved ants. But he was also fascinated by the wasps and other animals that lived in their nests with them, “behind enemy lines” as he put it. In the years that followed, the world changed. The Allies arrived in Germany. East and West were divided and set upon their separate paths. Meanwhile, the boy, Bert Hölldobler, remained devoted to ants. He began by studying species like those his father had collected during the war. Next, he resolved how the beetles that inhabit some ant nests find their hosts. Eventually, he came to study conflict. Warfare in ants can be ferocious. Ants pull at legs. They bite at antennae and heads. They spray formic acid and stab with their needle- Every army, insect or human, Nick Upton/naturepl.com like stings. It was not so much that Hölldobler marches on its stomach. A colony sought out the wars of ants: his approach was of honeypot ants is sustained by sugar stored in the swollen simply to study any ant that he happened upon, abdomens of immobile workers, in the hope of making new observations. But it which hang from the ceiling of was hard to ignore the fighting. the nest like Chinese lanterns. Honeypot repletes are a specialised caste of workers whose sole purpose is to act as living larders. Myrmecocystus workers attack a beetle larva, before hauling it back to the nest to feed the colony. A honeypot ant (left) picks a fight with a harvester ant in the Arizona desert. This view of the heart of a Myrmecocystus mimicus nest shows eggs, larvae, workers tending to repletes and (bottom left) one of the colony’s queens. Some clashes, like those of the pavement nectar. Their heads, legs and antennae are Most of the time, these ‘contests’, for want momentary territories – a piece of space and the peace. However, if one colony judges the going on right now, out in the desert, as you ant Tetramorium caespitum, seemed to drag tiny, but their golden bellies bloat to the size of a better word, resulted in a kind of time. The question was how. other to be small (that is, roughly a 10th of read this article, as they no doubt have done on, viciously, without end. Others were of marbles. During lean times, they share uneasy peace. But, every so often, full-scale To understand what was going on, the its own size), it attacks. for millions of years. harder to relate to his experience of human their stored goodness with those in need. wars broke out. scientist recorded thousands of hours of The desert floor is a hard place to be an warfare – or even to explain at all. Such Their wax and wane mark the seasons. When hostilities erupted, the resolution video of the ants and their contests. He up-and-comer. It is a geopolitical realm OF ANTS AND MEN was the case one day in Arizona when he The honeypots of Myrmecocystus was swift and dramatic. The filmed for two years, letting the tape roll as where only the old powers can share a truce. Hölldobler went on to study many other found himself out in the desert on his belly, have been eaten by desert-dwelling DID YOU KNOW? winning army would kill the the drama unfolded. What emerged from This is not the full extent of the complex kinds of ant, and in 1990 published the John Brown/johnbrownimages.co.uk staring, rapt, at the ground. people for generations (see box, Myrmecocystus workers of the rival colony, these observations, and later modelling world of ant politics, but a measure of it book on the subject (called simply The Ants). opposite). But this is not what mimicus colonies dispatch the queen, then carry efforts, was that the ants he had seen, acting anyway, and these complex manoeuvres are In doing so, he and co-author EO Wilson HONEY MONSTERS Hölldobler noticed that day in the may have several home the honeypots. Back in out their strange rituals, were, indeed, queens – up to six is Clockwise top from right: J Cancalosi/ Hölldobler checked for snakes, cleared desert. The scene looked more the nest, these abductees would assessing each other. not unheard of. Each ANTS ON THE MENU a spot and made himself as comfortable like a ritual than a biological may live for 20 years be tended to as a living larder, in or more, nearly all KNOW YOUR ENEMY as one can be out in the desert sun. Then phenomenon. It defied belief. much the same way that sailors Sweet-toothed humans have snacked on he proceeded to watch. His subjects were of which is spent in once kept live tortoises aboard The contests were bloodless, with warring honeypot ants since prehistoric times. female workers of the species Myrmecocystus RITUAL SPARRING total darkness. ships, to be eaten when needed. ants standing tall and even climbing on mimicus, an American honeypot ant. The ants ran towards each other, Hölldobler discovered that pebbles in order to assess their adversaries Ants have independently evolved honey Honeypot ants, as their name suggests, reared up as high as they could, then looked Myrmecocystus ants in general, and those based on some mix of individual size, the storage in deserts around the world: can store honey. The specialised workers that at one another, heads cocked. It was almost of the species M. mimicus in particular, numbers involved and other difficult to Myrmecocystus in North America, N perform this function, called repletes, hang as if they were sizing up their opponents feed on termites. Termites are a food worth discern calculations. Most days, that is the Camponotus and Melophorus in Australia, PL (captive); M Imamori/ other kinds in other places. Repletes hang. from the ceiling in a diminutive fighting for. Like cows, they are fat and end of it: two colonies, having asserted their An Australian aborigine of the nest. This version of West unprotected. But – unlike cows – they are respective size and status, manage to keep Honey is stored. Tough times are overcome tucks into a sweet is their only job. Side Story, staged hard to predict. through pluck and reserve. Camponotus replete. When conditions on a set of prickly Termites emerge in one place one day, only But ant societies are not the only ones for which history repeats itself. In what is now unrelated honeypot ant is harvested by a F are good, they pear and sand. to appear in another the next. It is difficult The contests were bloodless, LP A are fed by other Hölldobler for ants to defend such an ephemeral food the south-west USA, Native Americans have culturally unrelated race of people. ; x2 alexanderwild.com workers, mouth noticed certain source by establishing territories in the with warring ants standing long plundered the repletes of honeypot If there is a lesson here, it is this: in a to mouth, until patterns in the traditional manner. And so Hölldobler began ants, lying prone on the hot earth to dig desert, ants will work out how to store their abdomens ants’ behaviour. to wonder if perhaps it might not pay for tall and climbing on pebbles them out with sticks. Amazingly, the same sugar, and, if they store sugar, desert swell with sugary A youthful Bert Again and again, M. mimicus colonies to defend a single patch also happens in Australia, where a totally people will work out how to find it. honeydew and Hölldobler at they faced off. of ground for long. Maybe they defend more to assess their adversaries. work in the field. 68 BBC Wildlife December 2010 December 2010 BBC Wildlife 69 Myrmecosystus mimicus workers tend to a winged female ‘alate’. She will stay underground for weeks, waiting for the right conditions to launch her nuptial flight. John Brown/johnbrownimages.co.uk won a Pulitzer prize for their writing, Though Hölldobler himself can ignore the which included, dare I say it, his wartime parallels between ant and human conflict, as We have long studied ant journalism among the ants. a reader it is more difficult. One cannot help By the time of Hölldobler’s work on noticing, for example, that his studies of wars to better understand M. mimicus, there was already a long history honeypot ants coincided with the Cold War, of studying ant wars in order to better a quarrel in which two powers rattled sabres the travails of man. understand the travails of man. It was even at each other while consuming the world’s felt that generals could learn from their resources – not termites and nectar, yet the for what we should do. Hölldobler recently battles (he received two reprint requests for narrative was similar. confided this to me: “Wherever you find his first Myrmecocystus paper from the KGB We stand like the ants on our biggest highly co-operative societies, whether slime and CIA). But, for him, they remained just pebbles and try, again and again, to look moulds, insects or primates (including ants: lovely and complex, yet uncomplicated.